Twitter has come out publicly against Google’s recent changes to its search algorithm, which favors Google+ and Picasa results mixed in to regular search results.

TechCrunch has the details on the changes to Google’s search algorithm, which they’re calling “Your World”, but the basic idea is that results are now going to be peppered with data from Google+ and Picasa (which is Google-owned). Search results are going to be even more personalized to each user based on his or her Google+ posts, connections and activity.

Twitter’s General Counsel Alex Macgillivray tweeted that he believes this move heralds a “bad day for the Internet,” and goes on to say that he believes there must be some dissension at Google over the changes (having been Google’s own General Counsel prior to his current position at Twitter).

“For years, people have relied on Google to deliver the most relevant results anytime they wanted to find something on the Internet.

Often, they want to know more about world events and breaking news. Twitter has emerged as a vital source of this real-time information, with more than 100 million users sending 250 million Tweets every day on virtually every topic. As we’ve seen time and time again, news breaks first on Twitter; as a result, Twitter accounts and Tweets are often the most relevant results.

We’re concerned that as a result of Google’s changes, finding this information will be much harder for everyone. We think that’s bad for people, publishers, news organizations and Twitter users.”

Twitter used to appear in Google search results, up until July 2011 when the deal expired. Since then, Twitter’s CEO Dick Costolo offered some clarification, but provided little hope that the popular partnership would be renewed.

Google has responded to Twitter’s comments via (naturally) their Google+ account. And why not? That’s the best chance the message has of reaching the masses, after all.

We are a bit surprised by Twitter’s comments about Search plus Your World, because they chose not to renew their agreement with us last summer (http://goo.gl/chKwi), and since then we have observed their rel=nofollow instructions.

Search Engine Land’s Danny Sullivan has dug a little deeper into the story, speaking with Google executive chairman Eric Schmidt in this video.

You’ll note that Schmidt, while not exactly forthcoming, says it was Twitter who chose not to renew their deal with Google, which is the first time either side has shed any light on what happened in July. It’s very likely that Twitter will (at some point) come forward and say the exact opposite, but it’s also worth observing that, for his part, Schmidt says that Google is willing to talk to Twitter (and Facebook) about this issue.

Finally, Google’s Matt Cutts has expanded on what to expect from Google Your World in his blog. He does goes on (and on) about some party game called Werewolf, but it’s worth a read to get a little more insight into what we can expect.

Search plus Your World builds on the social search that we launched in 2009, and can surface public content from sites across from the web, such as Quora, FriendFeed, LiveJournal, Twitter, and WordPress.

The team should be finishing the rollout of Search plus Your World in the next day or so, and I hope you enjoy it. Remember, to see the new results, you’ll need to be signed in with a Google account and search on google.com. Give this new feature a whirl: once you see how much better personal search can be, I don’t think you’ll want to give it up.

You can expect more to unfold from this story over the rest of the week and we’ll update if and when we have additional information.